The Wanted singer gave the actress and American Idol judge a quick peck when the group performed on the show in April.
However, George stated that Keegan was actually jealous that she wasn't able to kiss the star herself.
"My girlfriend was jealous but not because I was with J Lo in that way," he told The Sun.
"It's because she wasn't with J Lo. She has a massive crush on her. If she met J Lo it would be me keeping an eye on them two.
"Saying that, I wouldn't mind watching - it would be great."
He added: "I've had worse days. Her boyfriend was watching in the audience as well which made it even naughtier.
"But she's easily one of the nicest stars we've met. She was perfect.
"When I went to see Manchester City towards the end of last season, I was at the bar at half-time with my mates and that's all they were asking about. They were buzzing."
The Wanted recently teased that they may be recording a duet with Jennifer Lopez in the future.
Michelle Keegan reportedly turned down Max George's second marriage proposal last month.